The only thing I don't like my skate-style shoe for is touring all day. I rarely find I am in the same position long enough and pedalling so constantly when MTBing that I get the hot spots.

That being said, I don't find my stiffer-soled more race style MTB shoes treacherous or slippery for walking up any steep bits. I actually find them better than my skate style shoes because they have nice big lugs on the sole and a pair of studs on the front of them that help me grip. Maybe it's the type of soil/dirt/rock here but I would choose them for grip over my Shimano skate style shoes anytime?